Investigating SEM metrology effects using a detailed SEM simulation and stochastic resist model

Richard A. Lawson; Clifford L. Henderson

doi:10.1117/12.2086051

19 March 2015 Investigating SEM metrology effects using a detailed SEM simulation and stochastic resist model

Richard A. Lawson, Clifford L. Henderson

Proceedings Volume 9424, Metrology, Inspection, and Process Control for Microlithography XXIX; 94240K (2015) https://doi.org/10.1117/12.2086051
Event: SPIE Advanced Lithography, 2015, San Jose, California, United States

Abstract

A Monte Carlo electron scattering simulation tool that can create SEM images of 3D features with arbitrary geometry has been developed. This is combined with both a stochastic resist model and synthetic 3D features to probe the effect of the effect of roughness on SEM measurements. Sidewall roughness makes it difficult to precisely identify the true feature width of a line because the roughness increases the SEM signal non-proportionally to the amount of material with which it is interacting. LER generally under predicts sidewall surface roughness because the SEM has an averaging effect as the electron beam interacts with a volume of material. LER becomes a better measure of surface roughness as the correlation length of the surface roughness increases. Decreasing film thickness causes a decrease in the linewidth and increase in LER measured by SEM, especially for features 35 nm thick and below. This occurs even if the true 3D feature width and roughness is approximately constant, meaning that the apparent change in linewidth and LER is a metrology effect. Threshold based estimations of line edges are difficult because the threshold choice that best matches the true feature width changes with the feature geometry. Model based library fits of linescans do not appear to provide a solution because sidewall roughness and sidewall angle have similar effects on the linescan meaning no unique linescan likely exists.

Citation Download Citation

Richard A. Lawson and Clifford L. Henderson "Investigating SEM metrology effects using a detailed SEM simulation and stochastic resist model", Proc. SPIE 9424, Metrology, Inspection, and Process Control for Microlithography XXIX, 94240K (19 March 2015); https://doi.org/10.1117/12.2086051

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available